Vijai Pandian column: When to shear winter burn damage

May 9, 2014

Healthy live buds are shown on winter burned yews. / Submitted

Winter burn damage shown on a boxwood. / Submitted

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Typically on evergreens, new growth emerges in late spring. On yews, boxwood, arborvitae, and Canadian hemlock with winter burn damage, check for live buds beneath those brown needles and along the shoot tips. Pinch one or two buds to see if the buds are still green inside. Also, check if the winter-burned shoots are still alive by scraping outer bark to see if the underlying tissue is green.

As the weather starts to warm up, the healthy, live buds will start to swell, and new green shoots will appear soon. Once the new growth appears, the dead brown needles will naturally wither off. After the emergence of new growth in late May to early June, shearing can be done and the dead shoots can be easily identified and can be pruned at the same time.

On dwarf Alberta spruce, if more than 40 percent of the bush is brown or nearly one half of the plant is brown, then it is better to trash the plant now. If the winter burn damage on dwarf Alberta spruce is less than 40 percent, you can try to salvage the plant by pruning those brown shoots. But be aware that it will take years for the new growth to fill in those void areas in the plant.

Conifers like pines produce new buds on the terminal ends. Check if the buds are alive by pinching the bud for any green tissue. If the buds are alive, the new growth (candles) will emerge in late May to early June, and the branch will continue to grow. The older brown needles will naturally wither off. However, if the terminal buds are dead, then prune off the entire shoot to its point of attachment.

Donít lose hope on those brown evergreens yet. Be patient and wait until late May to early June to prune them off.

Vijai Pandian is horticultural agent/educator for Brown County University of Wisconsin-Extension.